Portable plant health analysis system and method

ABSTRACT

A portable apparatus for analyzing a plant specimen. A housing assembly defines a sensing volume and controls entry of ambient light into the sensing volume when the housing is closed. A specimen support positions a plant specimen within the sensing volume whereby light emitted from at least one light emitter is incident upon the plant specimen. An image sensor senses light from the at least one light emitter that has been incident on the plant specimen. A processor analyzes data obtained from the light sensor to assess one or more properties of the plant specimen. There may be more than one light emitter, e.g., a halogen lamp and LED array, and the apparatus may acquire images under more than one lighting condition. The apparatus may include a mechanism for moving the plant specimen relative to the optical path to take images at multiple regions of interest on the specimen.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 16/658,838, filed Oct. 21, 2019 now U.S. Pat. No. 11,536,663 to Jinet al., which is a continuation application of international applicationPCT/US18/27953, filed Apr. 17, 2018, which claims priority fromprovisional application 62/546,699 filed Aug. 17, 2017, and which alsoclaims priority from provisional application 62/487,015 filed Apr. 19,2017, contents of each of which is incorporated herein by reference inits entirety into the present disclosure.

BACKGROUND 1. Technical Field

The present application relates to apparatus and systems useful inanalyzing plant health.

2. Description of the Related Art

The research community has developed and begun using a variety oftechnologies for plant phenotyping over the last decade. Thesetechnologies, however, are mainly directed toward research orientedusers working in academia and agricultural industries which havesignificant resources to fund the use of technology.

These new technologies have generally not been adopted by farmers whoare involved in growing agricultural crops for consumption and themarket. While many of the newly developed technologies used in theresearch community hold promise for such farmers, most farmers continueto rely on traditional methods of assessing the health of their crops.

SUMMARY

The present invention provides a portable system for assessing planthealth that is well-suited for use by individual farmers to assess thehealth of their crops. The system may employ hyperspectral imaging offluorescence, transmittance and/or reflectance to assess the health of aplant specimen.

The invention comprises, in a first embodiment thereof, a portableapparatus for analyzing a plant specimen. The apparatus includes ahousing assembly adapted to be carried between locations by a person,the housing assembly having a closed configuration wherein the housingassembly defines a sensing volume. The housing assembly controls entryof ambient light into the sensing volume when in the closedconfiguration. At least one light emitter is supported by the housingand positioned to emit light within the sensing volume when the housingis in a closed configuration. A specimen support is coupled with thehousing wherein the specimen support positions the plant specimen withinthe sensing volume whereby light emitted from the at least one lightemitter is incident upon the plant specimen when the housing is in aclosed configuration. An image sensor is positioned to sense lightwithin the sensing volume that has been emitted from the at least onelight emitter and incident on the plant specimen. A processor isoperably coupled with the at least one light emitter and the imagesensor to control operation of the apparatus whereby image data capturedby the image sensor is obtained to assess one or more properties of theplant specimen.

In a second embodiment, the apparatus of the first embodiment isconfigured to acquire images with the image sensor under a plurality ofdifferent lighting conditions.

In a third embodiment, the at least one light emitter of the secondembodiment includes a halogen light source, a laser light sourceemitting light in the range of 400 to 410 nm, or an LED array emittinglight within the range of 350 to 480 nm.

In a fourth embodiment, the at least one light emitter of the secondembodiment includes two different light emitters selected from the groupincluding a halogen light source, a laser light source emitting light inthe range of 400 to 410 nm, and an LED array emitting light within therange of 350 to 480 nm.

In a fifth embodiment, the at least one light emitter of the secondembodiment includes at least one halogen light source, at least onelaser light source emitting light in the range of 400 to 410 nm, and anLED array emitting light within the range of 350 to 480 nm.

In a sixth embodiment, the apparatus of the fifth embodiment isconfigured to capture a hyperspectral reflectance image, a hyperspectraltransmittance image and a fluorescent image of a region of interest onthe plant specimen in a single imaging sequence.

In a seventh embodiment, the apparatus of the sixth embodiment isconfigured such that, when the housing is in the closed configuration,the specimen support is positioned between the image sensor and a firsthalogen light source whereby the image sensor can capture ahyperspectral transmittance image from light transmitted through theplant specimen which has been emitted from the first halogen lightsource and wherein a second halogen light source, the laser light sourceand the LED array are positioned between the specimen support and theimage sensor whereby the image sensor can capture a hyperspectralreflectance image and a fluorescent image from light emitted from atleast one of the second halogen light source, the laser light source andthe LED array and reflected by the plant specimen.

In an eighth embodiment, the apparatus may take the form of any one ofembodiments 1 through 7 wherein the image sensor is a CMOS sensor or aCCD sensor.

In a ninth embodiment, the apparatus may take the form of any one ofembodiments 1 through 7 wherein the specimen support, the at least onelight emitter and the image sensor are all fixed relative to the housingassembly when the housing assembly is in the closed configuration.

In a tenth embodiment, the apparatus of the ninth embodiment isconfigured such that the housing includes a main body section and apivotal section wherein the pivotal section pivots relative to the mainbody between an open position providing access to the sensing volume anda closed position wherein the housing is in the closed configuration andwherein the specimen support is defined by engagement between thepivotal section and the main body.

In an eleventh embodiment, the apparatus of any one of embodiments 1through 7 is configured such that the light emitted from the at leastone light emitter and incident on the plant specimen that is sensed byimage sensor defines an optical path from the light emitter to the imagesensor, wherein the apparatus includes a plurality of optical componentsinteracting with the light defining the optical path and wherein the atleast one light emitter and the image sensor each define one of theplurality of optical components; and wherein a plant specimen engaged bythe specimen support is movable relative to at least one of theplurality of optical components in the optical path.

In a twelfth embodiment, the apparatus of the eleventh embodiment isconfigured such that the image sensor is adapted to acquire images undera plurality of different lighting conditions and wherein the apparatusis configured to move the plant specimen relative to at least one of theplurality of optical components in the optical path to thereby define aplurality of different regions of interest viewable by the image sensoron the plant specimen and wherein the apparatus is configured toacquire, at each region of interest, a plurality of images wherein eachof the plurality of images is subject to different lighting conditions.

In a thirteenth embodiment, the apparatus of the twelfth embodiment isconfigured such that the apparatus further includes a specimen positionsensor configured to obtain positional information on the plant specimenfor each of the plurality of regions of interest and wherein thepositional information is communicated to the processor.

In a fourteenth embodiment, the apparatus of the thirteenth embodimentis configured such that the specimen position sensor includes an encoderwheel engageable with the plant specimen.

In a fifteenth embodiment, the apparatus of the twelfth embodiment isconfigured such that the specimen support includes a specimen supportsurface slidably engageable with the plant specimen and the apparatusfurther includes a drive member engageable with the plant specimen, thedrive member slidingly moving the plant specimen along the specimensupport surface.

In a sixteenth embodiment, the apparatus of the fifteenth embodiment isconfigured such that the drive member is a cylindrical roller engagablewith the plant specimen.

In a seventeenth embodiment, the apparatus of the fifteenth embodimentis configured such that the drive member is positioned outside thesensing volume and the specimen support surface is configured to supportthe plant specimen as it travels from outside the sensing volume toinside the sensing volume and wherein the apparatus further includes atleast one light seal engageable with the plant specimen where the plantspecimen travels from outside to inside the sensing volume.

In an eighteenth embodiment, the apparatus of the fifteenth embodimentis configured such that movement of the plant specimen by the drivemember defines a travel direction and the specimen support surfacedefines a linear groove extending in the travel direction and adapted toreceive a rib of a leaf.

In a nineteenth embodiment, the apparatus of the fifteenth embodiment isconfigured such that the drive member is a cylindrical roller engagablewith the plant specimen and the plant specimen is positionable betweenthe drive member and specimen support surface, wherein movement of theplant specimen by the drive member defines a travel direction, andwherein the apparatus further includes a wedge-shaped engagement memberpositioned upstream of the drive member whereby the plant specimen ispositioned between the engagement member and the specimen supportsurface and encounters the engagement member before the drive memberwhen moving in the travel direction, the wedge-shaped member having anarrower end pointing way from the drive member whereby the engagementmember is configured to unfurl the plant specimen as it moves in thetravel direction.

In a twentieth embodiment, the apparatus of any one of embodiments 1through 7 is configured such that the at least one light emitterincludes a light enclosure assembly, the light enclosure assemblyincluding a light source disposed within an enclosure wherein theenclosure defines an opening through which light from the light sourceis emittable from the light enclosure assembly and wherein the lightenclosure assembly is positionable whereby the light emitted through theopening is incident upon the plant specimen and sensible by the imagesensor.

In a twenty-first embodiment, the apparatus of the twentieth embodimentis configured such that the light enclosure assembly includes a diffuserpositioned to diffuse light within the enclosure and an emitter lenspositioned to gather diffuse light from within the enclosure and directit outwardly from the enclosure through the opening.

In a twenty-second embodiment, the apparatus of the twenty-firstembodiment is configured such that the light enclosure assembly furtherincludes a reflector positioned to reflect direct light from the lightsource toward the diffuser and wherein the emitter lens is a cylindricallens and the opening in the light enclosure assembly is an elongate slithaving a length substantially greater than its width.

In a twenty-third embodiment, the apparatus of the twentieth embodimentis configured such that the light enclosure assembly wherein the lightsource is a halogen lamp and wherein interior surfaces of the enclosuresubject to light from the halogen lamp are formed by a materialincluding polytetrafluoroethylene.

In a twenty-fourth embodiment, the apparatus of the fifteenth embodimentis configured such that the at least one light emitter includes a lightenclosure assembly, the light enclosure assembly including a lightsource disposed within an enclosure wherein the enclosure defines anopening through which light from the light source is emittable from thelight enclosure assembly and wherein the light enclosure assembly ispositionable whereby the light emitted through the opening is incidentupon the plant specimen and sensible by the image sensor; wherein thelight source is a halogen lamp and wherein interior surfaces of theenclosure subject to light from the halogen lamp are formed by amaterial including polytetrafluoroethylene; and wherein a panel ofmaterial including polytetrafluoroethylene forms a portion of theenclosure, the panel defining one of the interior surfaces of theenclosure on a first side of the panel and forming the specimen supportsurface on the opposite side of the panel.

In a twenty-fifth embodiment, the apparatus of the twenty-fourthembodiment is configured such that movement of the plant specimen by thedrive member defines a travel direction and the opening in the lightenclosure assembly is an elongate slit having a length substantiallygreater than its width, the length of the slit extending in a directionperpendicular to the travel direction and wherein the panel defines alinear groove extending in the travel direction and adapted to receive arib of a leaf in the specimen support surface.

In a twenty-sixth embodiment, the apparatus of the twenty-fifthembodiment is configured such that the light enclosure assembly includesa polytetrafluoroethylene surface within the light enclosure assemblypositional to reflect light from the halogen lamp towards the slit andwherein the light enclosure assembly defines an exterior surface and atleast a portion of the exterior surface is formed by a metal material.

In a twenty-seventh embodiment, the apparatus of any one of embodiments1 through 7 is configured such that the light emitted from the at leastone light emitter and incident on the plant specimen that is sensed byimage sensor defines an optical path from the light emitter to the imagesensor, wherein the apparatus includes a plurality of optical componentsinteracting with the light defining the optical path and wherein the atleast one light emitter and the image sensor each define one of theplurality of optical components and wherein the apparatus furtherincludes a lens assembly disposed in the optical path the lens assemblyincluding a lens holder defining a passageway through which the opticalpath extends and having a lens disposed therein; and an adjustmentmember coupled with the lens and having a user-interface accessible by auser disposed on an exterior surface of the housing, the adjustmentmember configured to move the lens within the passageway based upon userinput received by the user-interface.

In a twenty-eight embodiment, the apparatus of the twenty-seventhembodiment further includes a diffraction grating disposed in theoptical path between the plant specimen and the image sensor.

In a twenty-ninth embodiment, the apparatus of any one of embodiments 1through 7 is configured such that the at least one light emitterincludes a plurality of LEDs and wherein the apparatus is configured toacquire images of the plant specimen under a plurality of differentlighting conditions with the image sensor, including hyperspectralimages and images wherein the light incident on the plant specimen iswithin a predefined wavelength band, the plurality of LEDs beingselectively actuated to generate a plurality of different predefinedwavelength bands whereby images can be acquired at each of the pluralityof different predefined wavelength bands.

In a thirtieth embodiment, the apparatus of the twenty-ninth embodimentfurther includes an LED switching circuit having a plurality of parallelbranches, each branch including an NPN transistor and controlling aportion of the plurality of LEDs wherein each portion of the pluralityof LEDs controlled by a separate branch defines a predefined wavelengthband.

In a thirty-first embodiment, the apparatus of the thirtieth embodimentis configured such that one of the branches controls LEDs emittinginfrared light.

In a thirty-second embodiment, the apparatus of the thirtieth embodimentis configured such that the plurality of LEDs include blue LEDs emittinglight with a wavelength within the range of 350 to 480 nm and whereinthe blue LEDs are illuminated with a halogen light source forhyperspectral imaging of the plant specimen and the blue LEDs are thesole source of incident light for acquiring a fluorescent image of theplant specimen at a predefined wavelength band.

In a thirty-third embodiment, the apparatus of the thirty-secondembodiment is configured such that the plurality of LEDs includenon-blue LEDs generating light outside the range of 350 to 480 nm andthe non-blue LEDs are used to acquire fluorescent images of the plantspecimen at at least one predefined wavelength band outside the range of350 to 480 nm.

In a thirty-fourth embodiment, the apparatus of any one of embodiments 1through 7 is configured such that the light emitted from the at leastone light emitter and incident on the plant specimen that is sensed byimage sensor defines an optical path from the light emitter to the imagesensor, wherein the apparatus includes a plurality of optical componentsinteracting with the light defining the optical path and wherein the atleast one light emitter and the image sensor each define one of theplurality of optical components and wherein the at least one lightemitter includes a plurality of LEDs and the apparatus further includesan LED support member, the LED support member being disposed between theplant specimen and the image sensor and having a central opening throughwhich the optical path extends, the plurality of LEDs being disposed onthe LED support member and circumferentially distributed about thecentral opening.

In a thirty-fifth embodiment, the apparatus of any of embodiments 1through 7 further includes a wireless communications transceiver coupledwith the processor and wherein the processor is configured to obtainlocational data through the transceiver and append acquired images withidentifying information, the identifying information includinglocational data.

In a thirty-sixth embodiment, the apparatus of the thirty-fifthembodiment is configured such that the processor is configured towirelessly communicate the acquired images and identifying informationto an external device.

A thirty-seventh embodiment takes the form of a method of using theapparatus of the thirteenth embodiment wherein the method includescommunicating the positional information about each region of intereston the plant specimen for each acquired image to processor andassociating the positional information with the relevant image, andutilizing the positional information about each image when analyzing theacquired images to assess the health of the plant specimen.

In a thirty-eight embodiment, the method of the thirty-seventhembodiment is performed such that the step of analyzing the acquiredimages to assess the health of the plant specimen includesdistinguishing between nitrogen hunger and potash deficiency of cornplant specimens.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features of this invention, and the mannerof attaining them, will become more apparent and the invention itselfwill be better understood by reference to the following description ofembodiments of the invention taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of a first embodiment of a portable system.

FIG. 2 is a partial perspective view of the first embodiment.

FIG. 3 is a cross sectional view of a portion of the first embodiment.

FIG. 4 is a schematic view of the first embodiment.

FIG. 5 is a flow chart of the operation of the first embodiment.

FIG. 6 is a flow chart of the calibration process.

FIG. 7 is a diagram showing interactions between users of the system.

FIG. 8 is a view of a plant specimen showing separate regions ofinterest for capturing images.

FIG. 9 is another view of a plant specimen showing separate regions ofinterest for capturing images.

FIG. 10 is a view of a corn plant having a plurality of leaves.

FIG. 11 is a chart showing imaging results obtained from the corn plantof FIG. 10 .

FIG. 12 is a chart showing imaging results obtained from the corn plantof FIG. 10 .

FIG. 13 is a chart showing imaging results obtained from the corn plantof FIG. 10 .

FIG. 14 is a chart showing imaging results obtained from a corn plantgrown in soil with a high nitrogen content.

FIG. 15 is a histrogram of the data depicted in FIG. 14 .

FIG. 16 is a chart showing imaging results obtained from a corn plantgrown in soil with a low nitrogen content.

FIG. 17 is a histrogram of the data depicted in FIG. 16 .

FIG. 18 is a cut-away perspective view of a second embodiment.

FIG. 19 is a partial schematic view of an assembly for moving a plantspecimen relative to the optical path of the assembly.

FIG. 20 is another partial schematic view of the assembly of FIG. 19 .

FIG. 21 a partial perspective schematic view of the assembly of FIG. 19.

FIG. 22 is a schematic side view of the assembly of FIG. 19 in an openposition.

FIG. 23 is a schematic side view of the assembly of FIG. 19 in a closedposition.

FIG. 24 is a schematic view of a light enclosure assembly.

FIG. 25 is a perspective view of a wedge-shaped member for unfurlingleaves.

FIG. 26 is a perspective view of another wedge-shaped member forunfurling leaves.

FIG. 27 is a schematic view of a light enclosure assembly.

FIG. 28 is a perspective view of an alternative apparatus.

FIG. 29 is a cut-aw ay perspective view of a focusing assembly.

FIG. 30 is a schematic view of an LED switching circuit.

FIG. 31 is a top view of a healthy corn leaf.

FIG. 32 is a top view of a corn leaf suffering from nitrogen hunger.

FIG. 33 is a top view of a corn leaf suffering from potash deficiency.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the exemplification set outherein illustrates embodiments of the invention, in several forms, theembodiments disclosed below are not intended to be exhaustive or to beconstrued as limiting the scope of the invention to the precise formsdisclosed.

DETAILED DESCRIPTION

A portable apparatus 20 for analyzing plant specimens is shown in FIGS.1-4 . Apparatus 20 is a portable device and is sized to allow it beeasily carried between locations by an individual person so that it maybe employed at the location where the plant specimen being analyzed hasbeen grown. Apparatus 20 includes a housing assembly 22 with a main body24 and a pivotal section 26. Pivotal section 26 is secured to main body24 with hinge assembly 28 that allows section 26 to pivot relative tomain body 24.

Housing assembly 22 defines an interior sensing volume 30 when in aclosed configuration (FIG. 1 ). Pivotal section 26 is pivotally moveablebetween an open position (see dashed lines in FIG. 4 ) and a closedposition (FIG. 1 ). By moving pivotal section 26 to its open position, auser can access sensing volume 30 and position a plant specimen foranalysis as further discussed below. Moving pivotal section 26 to itsclosed position secures the plant specimen and places housing assembly22 in its closed configuration. In its closed configuration, housingassembly 20 controls the entry of ambient light into sensing volume 30.In the illustrated embodiment, housing assembly 22 prevents the entry ofambient light into sensing volume 30 when in the closed configuration.By preventing all, or substantially all, entry of ambient light intosensing volume 30, the light used to capture images of the plantspecimen will be only that generated by apparatus 20 and can, thereby,be more precisely controlled.

Apparatus 20 includes a plurality of light sources or light emitterswhich are supported either directly or indirectly by housing assembly22. These light emitters are positioned to emit light into sensingvolume 30 when housing assembly 22 is in its closed configuration tothereby provide for the capture of one or more images of the plantspecimen as further discussed below.

A specimen support 32 is coupled with the housing and positions a plantspecimen 34 so that images of plant specimen 34 can be captured withapparatus 20. In the embodiment of FIGS. 1-4 , specimen support 32 isdefined by engagement between pivotal section 26 and main body 24 ofhousing assembly 22. More particularly, flexible, resilient seals 36encircle the openings to sensing volume 30 on both pivotal section 26and main body 24. Seals 36 may be formed out of a closed cell foam orother suitable material. Plant specimen 34 is positioned to extendacross the openings defined by seals 36 with pivotal section 26 in anopen position. Plant specimen 24 is then gripped between the two seals36 when pivotal section 26 is closed to thereby hold the specimen inplace so that light emitted from one of the light emitters that isincident upon the specimen can be captured by the image sensor.

An image sensor 38 is used to capture images of plant specimen and maytake the form of a CMOS (complementary metal-oxide semiconductor), CCD(charge coupled device), or other suitable sensor. In the embodiment ofFIGS. 1-4 , image sensor 38 is a CMOS sensor which is part of a digitalcamera assembly 40 which also includes a lens 42.

Apparatus 20 is configured to acquire images with image sensor 38 undera plurality of different lighting conditions. For example, apparatus 20can be used to capture a hyperspectral reflectance image, ahyperspectral transmittance image and fluorescent images of a region ofinterest on the plant specimen in a single imaging sequence. Plantspecimen 34 can then be repositioned and a series of images can becaptured at a different region of interest on the specimen.

Apparatus 20 includes several different light sources to provide thedifferent lighting conditions used to capture the images. As best seenin FIGS. 2 and 3 , apparatus 20 includes a first halogen light source inthe form of a halogen lamp 44 mounted on a light board 46 disposed inpivotal section 26 of housing 22. A second halogen lamp 48 is mounted onboard 50. Board 50 has a central opening 52 through which plant specimen34 is viewable by image sensor 38. A plurality of LEDs (light emittingdiodes) 54 are mounted on board 50 which thereby acts as an LED supportmember. LED support member/board 50 is positioned between specimensupport 32 (which holds plant specimen 34) and the image sensor 38. LEDs54 are circumferentially distributed about central opening 52. Apparatus20 also includes a laser light source 56 which projects light fromopening 58 onto the plant specimen.

Halogen lamps 44, 48, LEDs 54 and laser light source 56 all act as lightemitters which can be selectively actuated to generate light that isincident on plant specimen 34 and subsequently sensed by image sensor38. When actuated, the emitted light defines an optical path 37 from thelight emitter to the image sensor 38. Other optical components may alsointeract with the light along the optical path. In apparatus 20, theseadditional optical components include a slit 60, lens 62, diffractiongrating 64 and lens 42.

When housing assembly 22 is in the closed configuration for capturingimages, specimen support 32 is positioned between image sensor 38 andfirst halogen light source 44 whereby actuation of light emitter 44allows image sensor 38 to capture a hyperspectral transmittance imagefrom light emitted by source 44 and transmitted through plant specimen34.

Second halogen light source 48, laser light source 56 and the array ofLEDs 54 are all positioned between specimen support 32 and image sensor38 to thereby allow image sensor 38 to capture light from these sourceswhich has been reflected by plant specimen 34.

For example, image sensor 38 can capture a hyperspectral reflectanceimage generated by light emitted from halogen light source 48. LEDlights may be activated together with halogen light source 48 whenacquiring a hyperspectral reflectance image.

In the illustrated apparatus 20, halogen light sources 44, 48 aretungsten halogen light sources which provide a low cost light emitter.One drawback to tungsten halogen light sources, however, is that theyare weak in lower wavelengths in the blue and purple range. Apparatus 20includes LEDs 54 which emit light in the blue range and which may have awavelength between 430 to 505 nm. Advantageously, the blue LEDs usedwith apparatus 20 emit light having a wavelength between 430 and 480 nm.By activating the blue LEDs emitting light within a range from 430 to480 nm together with a tungsten halogen light source, a smooth anduniform lighting can be provided over a wide spectrum to provide highquality hyperspectral imaging.

The array of LEDs 54 in apparatus 20 includes not only blue LEDs butalso LEDs which emit light at other wavelengths within the range of 350nm to 480 nm. Distinct sets of LEDs emitting light within a limitedwavelength band are selectively activated to obtain multispectralimages. In other words, the blue LEDs may be activated to obtain a firstimage, LEDs emitting light in the red wavelength range may then beactivated to obtain a second image, LEDs emitting light in the yellowwavelength range may be activated to obtain a third image and LEDsemitting light in the green wavelength range may be activated to obtaina fourth image. Depending upon the type of plant and analysis beingperformed activation of these individual, distinct wavelength bands mayreveal useful information. For example, different proteins of interestmay be fluoresced by light emitted in the red, yellow and greenwavelength bands. LEDs emitting light in the infrared band may also beincluded in the array of LEDs mounted on board 50.

The various of light emitters in apparatus 20 may be used as anexcitation light source for acquiring more than one type of imagethereby providing a cost-effective assembly. For example, the blue LEDsmay be used together with a halogen light for a hyperspectral image andmay be the sole light sources activated for fluorescent imaging at bluewavelengths.

Laser light source 56 can also be activated to acquire a fluorescentimage. Advantageously, laser light source 56 can be used to emit lighthaving a wavelength in the range of 400 to 410 nm. Light within thiswavelength range, and most particularly at a wavelength of 405 nm,functions as an excitation light for chlorophyll in plant specimens andis, therefore, useful in assessing the chlorophyll content of the plantspecimen.

Image sensor 38 is advantageously a hyperspectral sensor instead of aRGB (red, green, blue) or grey scale sensor. This allows observation ofthe spectral response of fluorescence for each of the plant fluorescentresponses at differing wavelengths. This combination of “multipleexcitation bands” plus “hyperspectral fluorescent response” provides aunique imaging apparatus that can provide a wide range of plant healthinformation.

Apparatus 20 also includes a processor 66 which is operably coupled withthe light emitters 44, 48, 54, 56 and image sensor 38 to controloperation of apparatus 20 whereby image data captured by image sensor 38is thereby obtained to assess one or more properties of the plantspecimen 34. In the illustrated embodiment, processor 66 is a RaspberryPi which is commercially available from the Raspberry Pi Foundation inthe United Kingdom and is a single board computer that includes atransceiver 68 for wireless communication. ODROID by Hardkernel Co.,Ltd. of South Korea, and other processing units, may alternatively beused.

In the illustrated embodiment, embedded processor 66 can be connectedthrough transceiver 68 with a smartphone 70 wirelessly through Bluetoothor other wireless communication protocol. This arrangement allows theuser to operate apparatus 20 by using an application on smartphone 70.In this regard, it is noted that apparatus 20 could rely on an externaldevice, such as smartphone 70, to provide the processor necessary toprovide all of the control functions necessary for the operation ofapparatus 20, or, a smartphone, or similar communication device, couldbe an embedded part of apparatus 20.

Embedded processor 66, an application on smartphone 70, or a remoteexternal server in communication with smartphone 70 may be used toanalyze and process the image data acquired by apparatus 20 to assessvarious properties of the plant specimen such as chlorophyll content andother health parameters. For example, processor 66 may be configured towirelessly communicate the acquired images and identifying informationto an external device such as smartphone 70.

Advantageously, each of the acquired images are associated withidentifying information about the image and plant specimen. For example,labels or similar data packages may be associated with each image thatidentifies the light emitters used when acquiring the image, the type ofplant being examined, the location of the region of interest on theplant specimen captured in the image, a time stamp indicating when theimage was acquired and the geographical location where the plant wasgrown and/or the image acquired. Further information deemed useful couldalso be associated with the plant specimen. The time stamp andgeographical information can be easily generated by processor 66. Forexample, most processors include the ability to generate time stamps andmost telecommunication devices, such as smartphone 70, can identify thegeographical location of the smartphone. It is also possible for theuser to input data for association with the images. For example, anapplication on smartphone 70 could be used for such input.Alternatively, apparatus 20 could include a dedicated user input device.

By providing apparatus 20 with a wireless communications transceiver 68coupled with processor 66, processor 66 can be readily configured toobtain locational data through transceiver 68, e.g., from smartphone 70,and append acquired images with identifying information that includesthe locational data.

The GPS (global positioning system) precision of a typical smartphone isabout 3-6 meters in North America. Some plant breeding experiments haveplot sizes smaller than 3 meters. In such circumstances where greatergeographic precision is necessary to identify the specific plot of aplant specimen, processor 66 may be configured to allow the user toappend additional identifying information to the images and therebyidentify the specific experimental plot from which the specimen wasobtained. The identifying information will be part of the feature dataof each image or individual data package uploaded to the server, so theplant specimen data can be easily linked to specific plot locations.

The ability to append such geographic information to the data providesseveral benefits. For example, GIS (geographic information system)mapping data services can be provided with the geo-referenced planthealth data collected from many different locations over a geographicregion by one or more users employing one or more apparatus 20 which hasbeen uploaded to a cloud storage facility or other similar arrangement.The service may include real time data on regional plant growth stage,plant stresses (drought, nutrition, heat, insects, disease, etc.),regional crop yield predictions, climate impacts. If a representativesample of a region's agricultural producers can be included in the data,such data can be used to issue warnings to farmers who may thereby takesteps to mitigate or reduce threats to the crop and/or to policy makerswho may be thereby warn the general public and take steps to mitigate orreduce threats related to diminished food production for the region.

Current remote sensing technologies for precision agriculture provide atop view of the plant canopy at a relatively low resolution. Apparatus20 can provide detailed information on the lower leaves which arenormally more stressed. Apparatus 20 also has the potential to beimplemented in a fashion that allows apparatus to be moved between croprows to gather such additional information and provide phenotyping forthe lower leaves.

In the illustrated embodiment of FIGS. 1-4 and as can be seen in FIG. 1, apparatus 20 includes a power switch 72 for activating anddeactivating apparatus 20. Indicator lights 74 are used to communicateinformation to the user. Depressing button 76 initiates a communicationpairing process that connects processor 66 with an external device suchas a smartphone, for example, by using a Bluetooth pair process. Acharge port 78 is used to connect apparatus with an electrical powersource for charging one or more rechargeable batteries employed byapparatus 20. A data port 80 allows data to be transmitted betweenprocessor 66 and an external device. In some embodiments, apparatus 20may not include wireless communication capabilities and data port 80could be used to export data from apparatus 20. Port 80 may also be usedto update the operating software of apparatus 20 or to debug theapparatus.

FIGS. 5 and 6 are flowcharts representing the operation of apparatus 20.FIG. 5 presents a flowchart for acquiring an image using apparatus 20while FIG. 6 represents a calibration process. With regard to thecalibration process, it is noted that the reference image referred to inthe flowchart is a planar member with a surface having a known andpredefined color. For example, the reference image may be a whitesurface which allows the system to be calibrated to the known propertiesof this surface. It might alternatively be a grey surface or othercolored surface having known properties. Or, multiple reference imageshaving different properties might be used in the calibration process.

FIG. 7 is a diagram showing interactions between users of the system. InFIG. 7 , block 82 represents the users in the field employing apparatus20 to acquire data. Apparatus 20 communicates with a central computernetwork having cloud storage as represented by block 84. Apparatus 20uploads the acquired data and may also download updates to the softwareemployed by apparatus 20. For example, the models used to analyze theacquired data might be improved and updated and such improved modelscould be downloaded by apparatus 20. Block 86 represents agriculturalresearch institutions such as educational institutions and agriculturalindustry participants, e.g., seed companies, having their own researchfacilities. Such institutions would find the data acquired by apparatus20 to be quite useful, for example, in the development of new plantvarieties, and particularly when it is paired with geographicalinformation and/or specific experimental plot identificationinformation. Block 88 represents governmental and other policyorganizations. Such organizations may analyze regional information forguidance when setting agricultural policies or issuing warning or alertsto the agricultural producers or general public. Block 90 representsphenotyping research institutions which are involved in developingmethods to assess plant health based on the acquired images. Suchinstitutions may develop improved models for processing the image dataacquired by apparatus 20. It is also noted that there may, and likelywould be, overlap between the institutions identified by blocks 86, 88and 90. For example, it may be many of the same institutions who areinvolved in both the agricultural research of block 86 and thephenotyping research of block 90. Such institutions may also play a rolein developing policies for implementation by governmental bodies (block88) and such governmental bodies may also be involved in researchrepresented by blocks 86, 90.

When acquiring an image of a plant specimen, the mid-rib on the leaves,e.g., corn leaves, and veins on the leaf will typically impact theimaging result. Previous hand-held plant sensors are known to combineall the image data it collects to provide an average or other valuebased upon all of the gathered data. The embodiments described hereinemploy an image processing module to analyze the variance among thepixels and automatically remove outlier pixels which may be due to dust,spraying pollution, mid-rib, veins, etc., before calculating a valuebased on the image. This provides a higher signal over noise ratio.

As used herein, a region of interest refers to an area on a plantspecimen for which an image is captured for subsequent analysis. While aregion of interest may encompass an entire leaf, it will more typicallyencompass a smaller area at a particular location on a leaf. Theproperties of the leaf may vary for different regions of interest on theleaf depending upon the location of the region of interest. Such regionsof interest (“ROIs”) can be understood with reference to FIGS. 8 and 9 .FIG. 8 illustrates ten separate ROIs (numbered 1-10 in FIG. 8 ) whichextend along a line parallel to the mid-rib of the leaf from the tip ofthe leaf toward the base of the leaf. FIG. 9 illustrates three sets offour ROIs which extend along lines perpendicular to the mid-rib of theleaf. A first set of the ROIs is located near the tip of the leaf, asecond set is located near the middle of the leaf, and the third set islocated near the base of the leaf. Each of these three sets has fourROIs numbered 1-4 in FIG. 9 . As further discussed below, acquiringimages at a plurality of different ROIs at different locations on theplant specimen can provide for the acquisition of much more useful andinformative data.

Apparatus 20 shown in FIGS. 1-4 is configured such that specimen support32, light emitters 44, 48, 54, 56 and image sensor 38 are all fixedrelative to housing assembly 22 when housing assembly 22 is in theclosed configuration. To acquire images at multiple ROIs on a singlespecimen 34 using apparatus 20, the specimen must be manuallyrepositioned. To facilitate this, a separate case or cartridge forholding the plant specimen could be employed and the case or cartridgecould then be repositioned.

An alternative apparatus 100 is shown in FIGS. 18-23 and provides aportable apparatus having the same imaging capabilities as apparatus 20and further includes a mechanism for relative movement between plantspecimen 34 and the optical path defined by the apparatus whereby imagescan be acquired at multiple ROIs on the plant specimen without having tomanually reposition the plant specimen. In other words, apparatus 100 isconfigured such that the light emitted from a light emitter and incidenton plant specimen 34 that is sensed by image sensor 38 defines anoptical path from the light emitter to the image sensor. Apparatus 100includes a plurality of optical components interacting with the lightdefining the optical path with the light emitter and image sensor eachbeing one of the plurality of optical components. The plant specimenengaged by the specimen support is movable relative to at least one ofthe plurality of optical components in the optical path.

In the illustrated embodiment 100, it is plant specimen 34 which ismoved relative to the optical path. However, in alternative embodiments,one or more of the optical components could be moved relative to therest of the apparatus to thereby acquire images at different ROIs on theplant specimen. For example, apparatus 100 could employ a series ofmirrors with one or more of the mirrors being moveable to obtain such aresult.

Apparatus 100 is shown in FIG. 18 and includes a digital camera assembly102 having an image sensor 104 in the form of a CMOS sensor and lens106. Optical components disposed within sensing volume 136 of housingassembly 124 and positioned forward of lens 106 include a diffractiongrating 108, a lens 109, a slit 110, and a lens 112. It is noted that byusing a wide angle lens 112 the distance between the lens and thespecimen can be reduced and thereby provide for a more compact andlightweight apparatus. A transmittance light enclosure assembly 116 actsas a light emitter for light that is transmitted through the plantspecimen and is further described below. A reflectance light enclosureassembly 118 acts as a light emitter for light that is reflected by theplant specimen.

Apparatus 100 includes a controller assembly 120 which includes aprocessor and wireless communications capabilities and functions similarto processor 66 and transceiver 68. A rechargeable battery pack 122provides electrical power to the various elements of apparatus 100. Itis noted that internal wiring for control signals and electrical powerare not illustrated in the figures for either apparatus 20 or apparatus100 for purposes of graphical clarity.

Apparatus 100 is configured such that the image sensor 104 acquiresimages under a plurality of different lighting conditions and plantspecimen 34 is moved relative to at least one of the plurality ofoptical components in the optical path to thereby define a plurality ofdifferent regions of interest viewable by the image sensor 104 on plantspecimen 34. Similar to apparatus 20, apparatus 100 includes halogenlamps, an array of LEDs and a laser light source to generate thelighting conditions necessary for hyperspectral and multispectralimages. At each region of interest, a plurality of images subject todifferent lighting conditions are acquired.

In the illustrated embodiment, relative movement between the plantspecimen and one or more components of the optical path to provide aview of a different region of interest on the plant specimen is obtainedby moving the plant specimen relative to housing assembly 124 andmaintaining the optical path components in a fixed position relative tohousing assembly 124. In other words, the plant specimen is movedrelative to apparatus 100 to obtain images of different regions ofinterest on the plant specimen.

Movement of the plant specimen can be understood with reference to FIGS.19-23 which illustrate specimen support assembly 126. Specimen support126 includes a specimen support surface 128 on which plant specimen 34slides to reposition the plant specimen. A drive member 130 engages theplant specimen and selectively causes plant specimen 34 to slide alongsurface 128. In the illustrated embodiment, drive member 130 is acylindrical roller engageable with plant specimen 34. A spring 132biases the support surface 128 toward drive member 130 to thereby ensureengagement of the plant specimen 34 with drive member 130. Stop posts132 limit the travel of support surface 128 in the direction towardengagement member 130.

Similar to apparatus 20, housing assembly 124 of apparatus 100 enclosesa sensing volume 136 and controls the entry of ambient light intosensing volume 136 to provide high quality imaging of the plant specimenwhich takes place within sensing volume 136. In the illustratedembodiment, housing assembly 124 limits, and substantially prevents,entry of ambient light into sensing volume 136 when acquiring images ofthe plant specimen.

Drive member 130 is positioned outside sensing volume 136 and specimensupport surface 128 is configured to support the plant specimen as ittravels from outside sensing volume 136 to inside sensing volume 136.One or more flexible light seals 138 are provided and lightly engage theplant specimen at the location where the plant specimen travels fromoutside to inside the sensing volume 136.

A specimen position sensor 140 is used to obtain positional informationon the plant specimen for each of the plurality of regions of interestat which images are acquired and this information is communicated tocontroller/processor 120. In the illustrated embodiment, specimenposition sensor 140 takes the form of an encoder wheel that is engagedwith the plant specimen and which is positioned opposite drive cylinder130. As the plant specimen is slid along surface 128 it engages encoderwheel 140 and causes it to rotate an amount that corresponds to thelinear sliding travel distance of the plant specimen. This allows therelative positions of the regions of interest on the plant specimen tobe determined. The use of encoder wheels is well known to those havingordinary skill in the art.

Alternative arrangements may also be employed to provide a specimenposition sensor for apparatus 100. For example, the controls operating aservo motor driving cylindrical roller 130 could be used to calculatethe linear sliding distance of the plant specimen. Alternatively, imagesof the entire or large portion of the plant specimen could be acquiredand image processing techniques used to determine relative positions ofthe regions of interest on the plant specimen. Image mosaicingtechnologies, wherein multiple image strips or lines will be matchedwith adjacent images and then combined to form a larger image, may alsobe used to assess the movement distance between neighboring images.Another alternative would be to shine patterned light onto the leafsurface and track the reflectance change to measure the movementdistance in a manner similar to how an optical computer mouse functions.

When apparatus 100 records images of plant specimen 34 it acquiresimages of a limited area of the specimen that correspond to the regionsof interest depicted in FIGS. 8 and 9 . The use of a position sensorallows controller assembly 120 to determine the position of each regionof interest relative to the tip and base of the leaf. FIG. 9 illustratesthree separate locations, i.e, near the tip, near the middle and nearthe base, on the leaf where a set of four regions of interest can beacquired. In the illustrated embodiment slots 154, 168 control theemitted light and cause it to illuminate a small portion of the specimensample that would encompass the four regions of interest across thewidth of the plant specimen as depicted in FIG. 9 but not the entirelength of the plant specimen. Thus, images at the four regions ofinterest near the tip can be acquired without moving the leaf. The leafcan then be moved to allow images to be acquired at the four regions ofinterest in the middle of the leaf and then near the base. Individualregions of interest extending along the lull length of the leaf (asdepicted in FIG. 8 ) may also be acquired as the leaf is moved betweenthe positions indicated in FIG. 9 .

When acquiring images of the individual regions of interest on the plantspecimen, an image of a larger area may be acquired, e.g., encompassingfour regions of interest distributed across the width of the specimen,with the images then being cropped to limit the area encompassed by theimage to the selected region of interest or by simply limiting theanalysis to the particular regions of interest. An image of the entireleaf can be obtained by combining together the individual images of theleaf.

When acquiring such images it is desirable to communicate the positionalinformation about each region of interest on the plant specimen tocontroller/processor 120 so that it can be associated with the relevantimage. This positional information may originate with the positionsensor 140 and/or with an image processing software module used to cropthe images to define a particular region of interest. As discussedbelow, this positional information can be very helpful when it isutilized in the analysis of the images to assess the health of the plantspecimen.

FIG. 10 is a representation of a corn plant with the leaves labelled 4ththrough 13th. The 4th leaf is the lowest and oldest of the leaves andthe 13th leaf is the uppermost and youngest leaf. FIGS. 11-17 are chartsand diagrams displaying data obtained by taking images of corn leavessimilar to those depicted in FIG. 10 by fluorescing the leaves withlight having a wavelength of approximately 405 nm to assess thechlorophyll content of the specimen at the region of interest that hasbeen fluoresced. By measuring the response of a region of interest in acaptured image to the fluorescing light, a relative measure ofchlorophyll content can be obtained. Such relative measures may also becalibrated to quantitative chlorophyll content measurements.

As is evident from the data presented in FIGS. 11-17 , the chlorophyllcontent not only varies depending upon what leaf of the plant isselected but also varies between different locations on the same leaf.Taking only a single spot measurement will not provide the sameinformation that can be obtained with imaging data that is supplementedwith information regarding the location where, on the plant and/orindividual leaf, the region of interest that is the subject of the imageis located.

FIGS. 11-13 illustrate the measurements acquired at regions of interestthat correspond to FIG. 9 for most of the leaves of the plant depictedin FIG. 10 . As can be seen in these figures, the chlorophyll contentvaries depending upon whether the region of interest is located near thetip (FIG. 11 ), near the middle (FIG. 12 ) or near the base (FIG. 13 )of a particular leaf. As can also be seen in these figures, thechlorophyll content also varies depending upon the location of the leafon the plant with the tip area showing the greatest variation betweenleaves and the base area of the leaf showing the least amount ofvariation. It is noted that the identification of which leaf on a planta particular measurement corresponds to can be entered into theidentification field associated with particular images by manuallyentering that data when initiating a scan for a particular leaf.

FIGS. 14 and 15 display data acquired from the leaves of a corn plantgrown in soil having a high nitrogen content while FIGS. 16 and 17display data acquired from the leaves of a corn plant grown in soilhaving a low nitrogen content. The regions of interest for the datadisplayed in FIGS. 14-17 correspond to those depicted in FIG. 8 where alinear strip of regions of interest extend along the length of the leafand laterally offset from the center rib.

As evident from these figures, and the histograms of FIGS. 15 and 17 inparticular, patterns in the data can be used to distinguish between highand low nitrogen plants. Such patterns would not be present if a singlespot measurement or a single averaged measurement for each plant or eachleaf were used to compare the plants. Thus, it is evident from thesedata representations that pairing imaging analysis results withlocational data concerning provides value and information beyond thatprovided by spot measurements and averaged values.

FIGS. 31-33 provide a further illustration of how positional informationabout individual regions of interest can be useful when analyzing planthealth. FIG. 31 represents a leaf from a healthy corn plant wherein theentire leaf has a rich, dark, green color. FIG. 32 represents a leaffrom a corn plant suffering nitrogen hunger wherein the outer edges ofthe leaf are green but the central part of the leaf beginning at the tipis yellowing. FIG. 33 represents a leaf from a corn plant sufferingpotash deficiency wherein the central portion of the leaf is green butthe tip and outer edges of a lower leaf are yellowing. Taking aplurality of measurements at different regions of interest on the leavesdepicted in FIGS. 31-33 and averaging those values for each leaf wouldbe able to distinguish the healthy leaf from the other two leaves.Averaged values may not, however, be sufficient to distinguish the leafsuffering from nitrogen hunger from that suffering from potashdeficiency. Associating locational data with the imaging data, however,does provide a means for making such a distinction.

In this regard, it is noted that Normalized Difference Vegetation Index(NDVI) is a commonly used remote sensing technique that identifiesvegetation and measures the overall health of a plant. NDVI has been theused in the agricultural industry for many years. For example, it isknown to use a portable device from the Soil-Plant Analyses Development(SPAD) unit of Minolta Camera Co. of Japan such as the SPAD-052,commonly referred to as a SPAD meter, to measure chlorophyll content ofa leaf. The process typically involves randomly selecting samplingpoints on the first collar leaf of a plant. However, because such spotmeasures exhibit a high variability, an average value of multiplemeasurements are typically used.

Near infrared technologies may be capable of capturing an image of anentire leaf for analysis. However, it is conventional to calculate theNDVI for each pixel of such images and then use the average NDVI toevaluate the health of the plant.

One method for employing the locational information obtained with theapparatus of FIGS. 18-23 , is to calculate a modified NDVI index byusing a convolution integration method. A convolution vector or matrixis used to multiply the original NDVI vector or matrix to accentuate theimpact of the variance in values by location on the leaf.

Machine learning can be employed to calculate the convolution vector ormatrix. For example, samples of leaves from a high nitrogen soil (40 mMnitrogen, i.e., 40 millimolar which corresponds to well-fertilizedplants), medium nitrogen soil (i.e., 3 mM nitrogen, which corresponds tomoderate nitrogen stress) and low nitrogen soil (i.e., 1 mM nitrogen,which corresponds to severe nitrogen stress where the plants are barelyalive) can be employed with machine learning to calculate theconvolution vector or index. For example, a sample data table whichincludes positional information and has a size of m×n could bemultiplied by a convolution mask vector having a size of n×1 to obtain amodified NDVI index having a size of m×1 wherein m is the sample sizeand n is the number of features.

The resulting modified NDVI index showed a greater difference betweenthe high, medium and low nitrogen samples than the averaged NDVI values.

FIGS. 25 and 26 illustrate further features of the apparatus thatenhance the ability of the apparatus to move the plant specimen andobtain positional information. These features are particularly usefulwhen using apparatus 100 to assess the condition of leaves from a cornplant.

The edges of a corn leaf may curl inwardly toward the center or mid-ribof the leaf particularly if the leaf has a low moisture content. As canbe seen in FIG. 25 , a wedge-shaped engagement member 142 can bepositioned upstream of the drive member 130 to unfurl the leaves beforeacquiring images. The plant specimen is positioned between thewedge-shaped member 142 and specimen support surface 128 and engageswedge-shaped member 142 before the plant specimen engages drive member130 when moving in the travel direction 144 of the plant specimen.Wedge-shaped member 142 has a narrower end 146 pointing way from drivemember 130 whereby the wedge-shaped engagement member 142 unfurls theplant specimen as it moves in the travel direction 144. FIG. 26illustrates an alternative wedge-shaped member 143 that is formed by aprojection on a top cover member that is positioned opposite surface128.

As can be seen in FIGS. 25 and 26 , specimen support surface 128 mayalso include a linear groove 148 extending in the same direction astravel direction 144. Corn leaves, and leaves from many other plants,have a sizable central or mid-rib that extends the length of the leaf.Groove 148 receives the mid-rib and thereby facilitates the slidingmovement of the leaf along surface 128 in a straight direction andwithout compression damage.

FIG. 24 illustrates a light enclosure assembly 118 that can act as alight emitter for an apparatus disclosed herein. The light enclosureassembly 118 illustrated in FIG. 24 includes a light source 150positioned within an enclosure structure 152. Enclosure 152 defines anopening 154 through which light from light source 150 is emitted.Enclosure 152 is positioned so that the light emitted through opening154 is incident upon the plant specimen and sensible by image sensor104.

The embodiment illustrated in FIG. 24 includes a diffuser 156 positionedto diffuse light within the enclosure and an emitter lens 158 positionedto gather diffuse light from within the enclosure and direct itoutwardly from enclosure 152 through opening 154. Lens 158 takes theform of a cylindrical lens in the illustrated embodiment. A reflector160 is positioned to reflect direct light from light source 150 towarddiffuser 156. The use of such a diffuser provides more uniform light.Opening 154 may take the form of an elongate slit having a lengthsubstantially greater than its width whereby it generates light thatfalls incident on the plant specimen in a similar thin elongate shape.

FIG. 27 illustrates a light enclosure 116 which utilizes a halogen lamp162 as a light source disposed within an enclosure structure 164.Halogen lamps generate considerable heat and such heat can presentdifficulties. A layer or solid panel of polytetrafluoroethylene (PTFE)or material including PTFE, which is commercially available under thetrademark Teflon, is used to form the interior surfaces 166 of enclosure164 that are subject to light emitted from halogen lamp 162 to minimizeissues related to the generation of heat by lamp 162. Light from halogenlamp 162 is emitted through an opening 168 defined by enclosure 164.Opening 168 may be an elongate slit having a length substantiallygreater than its width. Use of elongate opening 168 confines theemission of light from halogen lamp 162 so that it is incident on anarea of the plant specimen that generally corresponds to the size andshape of opening 168. A panel with a PTFE surface 174 is advantageouslypositioned within enclosure 164 to reflect light toward opening 168. Inthe illustrated embodiment, the entire panel forming surface 174 isformed out of PTFE.

In the embodiment depicted in FIG. 27 , each of the panels used to formenclosure structure 164 is formed out of PTFE and with a metal claddinglayer 172 being disposed on the exterior surface of the PTFE panels onone or more sides of the enclosure. In the depicted embodiment, the PTFEpanel 170 which defines opening 168 has an inwardly facing surface 166and an outwardly facing surface on the opposite side of panel 170 thatforms specimen support surface 128. Metal cladding 172 is used to coverall of the exterior surfaces of enclosure structure 164 except for theexterior surface which forms specimen support surface 128. In theillustrated embodiment, cladding 172 is an aluminum material.

Panel 170 not only defines a slit 168 which extends entirely through thethickness of the panel but also defines a groove 148 that does notextend through the full thickness of the panel and which is located onspecimen support surface 128. Elongate slit 168 has a lengthsubstantially greater than its width with the length of the slitextending in a direction perpendicular to travel direction 144 whilelinear groove 148 extends in travel direction 144 and is adapted toreceive a central rib of a leaf.

FIG. 28 illustrates an apparatus which includes a light enclosureassembly 116 that can be repositioned within housing assembly 176 withlinkage assembly 178. A servo motor (not shown) can be used to rotate anupper member of linkage assembly 178 to thereby slide enclosure 116. Byusing an elongate slit 168 with a moveable enclosure 116 it would bepossible to provide a means for obtaining images at a series of spacedapart regions of interest as depicted in FIGS. 8 and 9 .

In some embodiments, it may be desirable to provide a mechanism forfocusing one or more of the lens which are located in the optical pathbetween the light emitter and the image sensor. If a conventionaldigital camera is adapted for use with the apparatus, the lenspositioned immediately proximate the image sensor may include a focusingmechanism that is provided with the camera assembly. If such a focusingarrangement is not provided as part of a digital camera assembly and/orto focus another lens employed in the apparatus, a focusing assembly 180as depicted in FIG. 29 can be employed with the lens.

Focusing assembly 180 includes a lens holder 182 which defines apassageway 184 in the form of a cylindrical bore. Optical path 186extends through passageway 184 and through a lens 188 disposed therein.An adjustment member 190 engages a collar 192 in which lens 188 issecured. Member 190 has a user-interface 194 on the exterior surface ofthe apparatus in the form of a slot that can be engaged with a flat headscrew driver to rotate member 190. Member 190 also has an off-centerpost 196 that engages a slot 198 in collar 192. As member 190 isrotated, post 196 causes collar 192 and lens 188 mounted therein to movealong optical path 186 in passageway 184 to thereby focus lens 188. Asnap ring 202 maintains member 190 within holder 182. This arrangementallows a user to focus lens 188 from the exterior of the apparatus withonly a screw driver. Alternatively, a feature on member 190 that can begrasped by the hand of a user could be employed. The use of slot 198,however, helps to prevent inadvertent movement of member 190.

As discussed above, by providing the apparatus with an array of LEDs,the selective activation of such LEDs either alone or in combinationwith other light sources can be used to acquire images of the plantspecimen under a plurality of different lighting conditions with theimage sensor, including hyperspectral images and images wherein thelight incident on the plant specimen is within a predefined wavelengthband. By providing LEDs which emit light at different wavelengths, theLEDs can be selectively actuated to generate a plurality of differentpredefined wavelength bands whereby images can be acquired at each ofthe plurality of different predefined wavelength bands. For example,LEDs emitting light in the red, yellow and green wavelength band couldeach be separate actuated to acquire different images of a specimen.

While the actuation of such different groups of LEDs can be accomplishedwith the controller 120 or processor 66 alone, FIG. 30 provides anexample of a dedicated circuit that provides for a more rapid switchingbetween groups of LEDs to thereby speed up the acquisition of multipleimages under different lighting conditions. Circuit 204 is an LEDswitching circuit that includes a plurality of parallel branches 208,210, wherein each branch includes an NPN transistor 206. Each branchcontrols a portion of the plurality of LEDs wherein each portion of theplurality of LEDs controlled by a separate branch defines a predefinedwavelength band. In the example of FIG. 30 , branch 208 controls LED 212which emits infrared light and branch 210 controls LED 210 which emitswhite light. A power source 216 provides the electrical energy for theLEDs and controller 120 controls the operation of NPN transistors 206.

While one example of such a circuit has been illustrated in FIG. 30 ,such a circuit may include additional parallel branches to therebycontrol a greater number of different groups of LEDs emitting light atdifferent wavelength bands. For example, in some embodiments, theplurality of LEDs include blue LEDs emitting light with a wavelengthwithin the range of 350 to 480 nm with the blue LEDs being illuminatedwith a halogen light source for hyperspectral imaging of the plantspecimen and the blue LEDs being the sole source of incident light foracquiring a fluorescent image of the plant specimen at a predefinedwavelength band. Such an embodiment may also include non-blue LEDsgenerating light outside the range of 350 to 480 nm with the non-blueLEDs being used to acquire fluorescent images of the plant specimen atone or more predefined wavelength bands outside the range of 350 to 480nm.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles.

The invention claimed is:
 1. A method for analyzing a plant specimen,comprising: emitting light by at least one light emitter positioned toemit light within a sensing volume within a housing assembly when thehousing assembly is in a closed configuration, the at least one lightemitter comprising a first halogen light source, a second halogen lightsource, a laser light source, and a light emitting diode (LED) array,wherein the housing assembly controls entry of ambient light into thesensing volume when in the housing assembly in the closed configuration;supporting a plant specimen by a specimen support coupled with thehousing assembly wherein the specimen support configured to position theplant specimen within the sensing volume whereby light emitted from theat least one light emitter is incident upon the plant specimen when thehousing assembly is in the closed configuration; sensing light by animage sensor positioned within the sensing volume, light emitted fromthe at least one light emitter and configured to be incident on theplant specimen; and controlling light emitted by the at least one lightemitter; capturing image data by the image sensor; assessing one or moreproperties of the plant specimen from the captured image data captured;positioning the specimen support between the image sensor and a firsthalogen light source; capturing a hyperspectral transmittance image bythe image sensor from light transmitted through the plant specimen whichhas been emitted from the first halogen light source; and capturing ahyperspectral reflectance image and a fluorescent image from lightemitted from at least one of a second halogen light source, the laserlight source and the LED array and reflected by the plant specimen, whenthe second halogen light source, the laser light source and the LEDarray are positioned between the specimen support and the image sensor.2. The method of claim 1, wherein capturing image data by the imagesensor is under a plurality of different lighting conditions.
 3. Themethod of claim 2, wherein the laser light source is configured to emitlight in the range of 400 to 410 nm.
 4. The method of claim 2, whereinthe LED array is configured to emit emitting light within the range of350 to 480 nm.
 5. The method of claim 2 the laser light source isconfigured to emit light in the range of 400 to 410 nm and an LED arrayis configured to emit light within the range of 350 to 480 nm.
 6. Themethod of claim 1, wherein the captured hyperspectral reflectance image,the captured hyperspectral transmittance image and further capturing afluorescent image of a region of interest on the plant specimen areprovided in a single imaging sequence.
 7. The method of claim 1, whereinthe image sensor is a CMOS sensor or a CCD sensor.
 8. The method ofclaim 1, wherein the specimen support, the at least one light emitterand the image sensor are all fixed relative to the housing assembly whenthe housing assembly is in the closed configuration.
 9. The method ofclaim 8, wherein the housing assembly includes a main body section and apivotal section wherein the pivotal section pivots relative to the mainbody between an open position providing access to the sensing volume anda closed position.
 10. The method of claim 1 wherein the at least onelight emitter includes a light enclosure assembly, the light enclosureassembly comprising a light source disposed within an enclosure whereinthe enclosure defines an opening through which light from the lightsource is emittable from the light enclosure assembly and wherein thelight enclosure assembly is positionable whereby the light emittedthrough the opening is incident upon the plant specimen and sensible bythe image sensor.